From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Reiser Subject: Re: plugin for cached network file system Date: Wed, 12 May 2004 22:49:07 -0700 Message-ID: <40A30C53.3020607@namesys.com> References: <200405131059.22693.Michael.James@csiro.au> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <200405131059.22693.Michael.James@csiro.au> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Michael.James@csiro.au Cc: reiserfs-list@namesys.com Michael James wrote: >How hard would it be to write a Reiser4 plug-in > to implement a network file system with a cache on the local disk? > >By caching I mean an incomplete local mirror > of the master filesystem on the network server > with on-demand loading and a simple flushing algorithm. >So open calls to files in the cached area are intercepted > and if the file isn't already in place a script is called to get it there. >THEN the open call returns the file-handle normally. > >I only need the simplest case of a distributed file system: > - nodes are only reading the files, > - files only change slowly (~weekly) > so cached files could be assumed fresh for a day at a time > or even flushed with: rsh node 'rm -r /cache/*' > - any network code could be avoided by NFS mounting the master copy, > so fetching a new file is still just a local cp off the NFS mount. > > >The situation is that CSIRO'S Bioinformatics Facility > has two 400Gig filesystems on a server, > that need to be available to 66 cluster nodes. >Just NFS exporting one server to so many nodes leaves the cluster NFS bound. >(Should I say they are Dell Perc 3 controllers and slow-as...) > >Jobs come in big batches each reading the same 2 - 6 Gig file. >Each node has 27 Gig of free space so it's heaps for the working set > I just don't want to have to groom what is in this working set for each job. >Nor do I want to have to pre-pend an rsync to a batch. > >Has anyone written something that could be bent to this purpose? >Is there template code for a Reiser4 plug-in? >Or what would it cost to get it written? > >michaelj > > > > It is easy to do a hack, and hard to do it right so that the world would want to drop nfs and move to it. We are trying to find a sponsor to do it right, and have a proposal called Reiser5 that costs $1.8 million, and provides global scalability (which nfs/afs/clusterfs/intermezzo do not, in my view). Hans